bpulv Loc: Buena Park, CA

How do you one iMac with a second one used as a monitor with Photoshop and Lightroom without losing LR/PS functions?

I just cabled my two 27” iMacs so that my 2018 model acts as the computer and my mid-2010 iMac is a dumb slave monitor. The two work together well for Mac software, but when you put LR on one screen and PS on the other, several problems appear that I will discuss in a moment. The new computer has OS 10.14.1 Mojave and the old computer uses the latest version of High Sierra (it cannot be upgraded to Mojave).

When I run LR on one monitor and PS on the other, I cannot get the tray to appear in spite of the fact that Apple’s tech people checked all of my system preferences are said they are set correctly. In addition, both programs can only be viewed in full screen mode and cannot be adjusted in size and the red, yellow and green dots in the upper left of the LR screen cannot be viewed or accessed while the PS screen shows the red, yellow and green dots, but they do not work. If you click on the green dot in PS, the screen momentarily changes mode but quickly returns to full screen. There is additionally a problem with LR and the iMac's brightness level. Although both monitors are calibrated twice month, the LR screen's image is very dark. Also, I understand that there is a way to have your PS picture on one screen and the tools on the other. Is that correct? If so, how do you set that up.

Please do not confuse me with speculation. I would appreciate it if only UHH members with hands on experience using LR and PS in this manner respond.

Thank you for your help and cooperation.

Dngallagher Loc: Wilmington De.

I use an 2015 iMac as my primary and my older iMac in target display mode connected via thunderbolt cable as a second monitor.

My Mac sees the older Mac as a secondary display and it functions properly as a secondary display. I have not seen the issues you describe, but I have not had Lightroom on one screen and Photoshop on the other, will give that a try tonight.

I have High Sierra on the older Mac and Mojave on the newer Mac.

I always have apps split between the two monitors with no problems.

bpulv Loc: Buena Park, CA

Thank you for your response. I look forward to any other information you can find.

Dngallagher Loc: Wilmington De.

I am able to have Lightroom Classic CC on my left hand monitor (when in normal screen mode in Lightroom) and Photoshop on the right hand monitor, no issues.

My Macs are connected via a thunderbolt cable and my left hand screen is my older mac running in target display mode (command F2)
Make sure your Lightroom is in NORMAL SCREEN MODE.

Lightroom can also manage two screens, one for grid mode & one for loupe mode or various other combinations. Available from the little 2 screen bottom left.

I am able to minimize both or either screen, then maximize either or both back to where they were. I have a dock on both monitors as well as a top status bar on both monitors, all functional.